Unless otherwise indicated herein, the materials described herein are not prior art to the claims in the present application and are not admitted to be prior art by inclusion in this section.
PV modules used in solar energy systems are often installed at an inclined angle (e.g., tilt) and aligned to the sun, e.g., generally facing south in the Northern Hemisphere or generally facing north in the Southern Hemisphere. The angle and alignment improve energy output, snow performance, and cooling while reducing soiling compared to horizontal configurations. At many northern and southern latitudes, the tilt of the PV modules causes significant shading behind the modules, with the extent of the shading generally varying between the most shading on the winter solstice and the least shading on the summer solstice.
For example, FIG. 1 illustrates an example of the extent of shading for PV modules on the winter solstice (e.g., left side) versus the summer solstice (e.g., right side), arranged in accordance with at least some embodiments described herein. As illustrated in FIG. 1, the tilt angle also affects the amount of shading. In more detail, the top of FIG. 1 includes PV modules inclined at about 15 degrees from horizontal, while the bottom of FIG. 1 includes PV modules inclined at about 30 degrees from horizontal. It can be seen from FIG. 1 that the greater incline angle extends the shading a greater distance behind the PV modules.
Unfortunately, the electrical topology of some conventional PV modules results in a severe energy production penalty during any systematic shading event. In particular, such conventional PV modules have long strings of series-connected PV cells where energy production can be bottlenecked by a single shaded or underperforming PV cell. Such PV modules typically include bypass diodes, each of which allows current to bypass a different section of the string. The bypass diodes that protect each section of the string open when the voltage is back-biased due to an imbalance in photo-generated currents, causing some of the sections of the string to be shunted out of the circuit.
Accordingly, such conventional PV modules are often spaced so as to avoid any adjacent module shading at the worst-case scenario (e.g., winter solstice). As the angle of the incoming light changes throughout the year and into summer, however, much of the incoming light is then incident on unproductive space and its energy is lost from the solar energy system.
Another option is to install the PV modules without any tilt to avoid any adjacent module shading and to allow the PV modules to be installed relatively more densely. In the absence of tilt, however, dirt, debris, snow, etc. can accumulate on the PV modules and reduce their energy output. In contrast, for a tilted PV module, the effects of gravity alone and/or in combination with precipitation and/or wind can generally keep the PV modules relatively more clear of dirt, debris, snow, etc.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.